From around age 8 through high school I read multiple books per week. Just DEVOURED them. In 3rd and 4th grade these were things like Goosebumps, The Baby-Sitters Club, Roald Dahl, and Bruce Coville. I was so enamored with Roald Dahl that I had planned to send him a letter asking for his autograph– and my 3rd grade teacher had to gently break the news to me that he was dead. DEAD!! I feel bad for her, I surely did not take it well.

It is not possible to pick a favorite. I was really excited to start buying these for my niece when she turned 7.
By age 10 it was clear that kid’s books were not holding me anymore, and there were only so many installments of The Baby-Sitters Club to be found in local library used book sales, so the summer before fifth grade I skipped YA (did it even exist at the time?) and went straight to reading my mom’s books. So basically I have this 2-3 year period of formative childhood books.
Aside: There were 131 books in the main Baby-Sitters Club series, plus numerous spin-offs and special issues. Though now that I look it up on Wikipedia, Ann M. Martin only wrote the first 35 and the rest were ghost-written, mostly by some guy named Peter?? I FEEL SO BETRAYED. I also wrote for her autograph, which I received, but which in later years I realized was a mass-printed photo of her with signature included. A childhood of lies.
It must be noted that I was Team Claudia all the way. She was Japanese, and into art, and had fuuunky style, and ate tons of junk food. I even had this amazing Claudia doll with overalls, a puffy pirate shirt, and pink tights. Oh ho ho, that was so Claudia.
Even though I transitioned to adult books when I was 10, I didn’t entirely cut off the great authors of my youth. You don’t just STOP reading new Bruce Coville books! Unlike Ann M. Martin he actually WROTE all of his books. Wikipedia tells me that his previous jobs included toymaking and gravedigging, and that is all I need or care to know about the man. My Teacher is an Alien, Jeremy Thatcher Dragon Hatcher, it was all gold.
So I had a few more years leading into junior high in which I was still reading R.L. Stine alongside Stephen King. Another series that has a fond place in my memory was the Animorphs by K.A. Applegate, which my brother first started reading and then got me into. In this series I was aaaalll about Tobias. That boy got his ass stuck as a bird like on DAY ONE of animorphing, and it was just so tragic.
Second-best to Tobias was CLEARLY Cassie, who worked at a wildlife rehab clinic with her parents, and was a total pacifist but still had to suck it up and do battle with aliens for the sake of all humanity.
I was so into the Animorphs that I wrote my own rip-off book about kids fighting aliens– except mine was in SPACE, which is clearly superior, and I don’t even remember who they were fighting but it was probably better than brain slugs. My book was called Fateful Encounters, Book One of The Galaxy Chronicles. It was about 180 pages and it was so melodramatic and awful but I wrote it in six frenzied days during summer vacation, and that’s got to count for something.